1312331021 has 4 divisors (see below), whose sum is σ = 1312511232. Its totient is φ = 1312150812.

The previous prime is 1312331017. The next prime is 1312331071. The reversal of 1312331021 is 1201332131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1201332131 = 647 ⋅1856773.

It is a cyclic number.

It is not a de Polignac number, because 1312331021 - 2² = 1312331017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1312331071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78701 + ... + 93906.

It is an arithmetic number, because the mean of its divisors is an integer number (328127808).

Almost surely, 2^1312331021 is an apocalyptic number.

It is an amenable number.

1312331021 is a deficient number, since it is larger than the sum of its proper divisors (180211).

1312331021 is an equidigital number, since it uses as much as digits as its factorization.

1312331021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180210.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1312331021 is about 36226.1096586426. The cubic root of 1312331021 is about 1094.8327958592.

Adding to 1312331021 its reverse (1201332131), we get a palindrome (2513663152).

It can be divided in two parts, 13123 and 31021, that added together give a palindrome (44144).

The spelling of 1312331021 in words is "one billion, three hundred twelve million, three hundred thirty-one thousand, twenty-one".